/*
 * Copyright 2020 by OLTPBenchmark Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

package com.oltpbenchmark.distributions;

/**
 * A generator that is capable of generating ints as well as strings
 *
 * @author cooperb
 */
public abstract class IntegerGenerator extends Generator {
  int lastint;

  /**
   * Set the last value generated. IntegerGenerator subclasses must use this call to properly set
   * the last string value, or the lastString() and lastInt() calls won't work.
   */
  protected void setLastInt(int last) {
    lastint = last;
  }

  /**
   * Return the next value as an int. When overriding this method, be sure to call setLastString()
   * properly, or the lastString() call won't work.
   */
  public abstract int nextInt();

  /** Generate the next string in the distribution. */
  public String nextString() {
    return "" + nextInt();
  }

  /**
   * Return the previous string generated by the distribution; e.g., returned from the last
   * nextString() call. Calling lastString() should not advance the distribution or have any side
   * effects. If nextString() has not yet been called, lastString() should return something
   * reasonable.
   */
  @Override
  public String lastString() {
    return "" + lastInt();
  }

  /**
   * Return the previous int generated by the distribution. This call is unique to IntegerGenerator
   * subclasses, and assumes IntegerGenerator subclasses always return ints for nextInt() (e.g. not
   * arbitrary strings).
   */
  public int lastInt() {
    return lastint;
  }

  /** Return the expected value (mean) of the values this generator will return. */
  public abstract double mean();
}
